The use of wireless communications in everyday life has become ubiquitous. Information is transmitted wirelessly using a variety of different techniques on an increasing number of radio frequency (RF) bands. Communication devices typically convert between the RF signals and low frequency (LF) signals such as intermediate frequency (IF) signals or zero-frequency signals such as baseband signals as the components in the devices operate on the LF signals. In particular, during reception, the communication device typically receives and amplifies an RF signal before modulating the RF signal to an LF signal. The LF signal is then typically digitized and the digitized signals then being further processed by digital circuitry (e.g., microprocessors, digital signal processors, etc.).
The desired (in band) RF signals, however, are not the only RF signals present during processing. Blocker (out of band) signals also affect the components used to receive the signals. The out of band RF signals, for example, may be generated for transmission by the same communication device and leak into the receiver path. A typical receiver path contains, among other components, an amplifier that amplifies the RF signal, a mixer that converts the RF signal to an LF signal and an analog-to-digital converter (ADC) that converts the LF signal into digital data. The out of band RF signals cause a number of issues in an architecture in which the mixer is directly connected to the ADC, including degraded linearity and increased noise figure of the overall receiver.
What is desired is an improved receiver and method that addresses these issues.